Perinatal mortality in Bavaria, Germany, after the Chernobyl reactor accident

Considerations of Medical Preparedness to Assess and Treat Various Populations During a Radiation Public Health Emergency

During a radiological or nuclear public health emergency, given the heterogeneity of civilian populations, it is incumbent on medical response planners to understand and prepare for a potentially high degree of interindividual variability in the biological effects of radiation exposure. A part of advanced planning should include a comprehensive approach, in which the range of possible human responses in relation to the type of radiation expected from an incident has been thoughtfully considered. Although there are several reports addressing the radiation response for special populations (as compared to the standard 18-45-year-old male), the current review surveys published literature to assess the level of consideration given to differences in acute radiation responses in certain sub-groups. The authors attempt to bring clarity to the complex nature of human biology in the context of radiation to facilitate a path forward for radiation medical countermeasure (MCM) development that may be appropriate and effective in special populations. Consequently, the focus is on the medical (as opposed to logistical) aspects of preparedness and response. Populations identified for consideration include obstetric, pediatric, geriatric, males, females, individuals of different race/ethnicity, and people with comorbidities. Relevant animal models, biomarkers of radiation injury, and MCMs are highlighted, in addition to underscoring gaps in knowledge and the need for consistent and early inclusion of these populations in research. The inclusion of special populations in preclinical and clinical studies is essential to address shortcomings and is an important consideration for radiation public health emergency response planning. Pursuing this goal will benefit the population at large by considering those at greatest risk of health consequences after a radiological or nuclear mass casualty incident.

Assessment of the potential impacts of the Chernobyl nuclear disaster on maternal and fetal health in Hungary

Objective: Radiation exposure is known to be mutagenic and teratogenic. The aim of this study was to analyze the effects of the increased ionizing radiation emitted by the Chernobyl nuclear disaster on maternal and fetal outcomes in Hungary.Methods: A retrospective analysis of abortion, stillbirth, and congenital anomaly data for pregnancies in Hungary between 1 January 1981 and 31 December 1991 was conducted.Results: Trend analysis revealed increasing trends in spontaneous and voluntary abortion rates in Hungary during the study time period, while late pregnancy losses showed a decreasing trend. Overall, there were generally decreasing incidence rates for birth defects throughout the 1980s. Increased voluntary abortions over the study period might reflect, at least in part, maternal anxiety in the post-Chernobyl years. Decreased late pregnancy loss over the same period may be attributable to improvements in prenatal diagnostics. A notable weakness of this study is that missing data could not be complemented due to the decades that have passed since the incident.Conclusions: In conclusion, the present data suggest that the nuclear catastrophe in 1986 did not cause a significant increase in pregnancy loss or congenital malformations in Hungary.

Perinatal mortality after the Fukushima nuclear accident: An ecological study

OBJECTIVE

This study continues former studies on perinatal mortality in Japan after the Fukushima Daiichi nuclear power plant (FDNPP) accident in March 2011. An increased study region is chosen, and the study period is extended to 2019.

METHODS

Japanese monthly perinatal mortality data are provided on a prefecture level by the Japanese government. The study region consists of 12 prefectures around the FDNPP; the rest of Japan is used as the control region. A combined non-linear regression of perinatal mortality rates in the study- and control regions is conducted. The regression model allows for a common asymptotic lower limit of perinatal mortality, seasonal variations, and periodic peaks in 2012-2019 in the study region. To determine the dependency of the effect on distance from the FDNPP, the study region is divided into four core prefectures and eight prefectures surrounding the core prefectures.

RESULTS

Perinatal mortality rates in the study region show a significant 6.4% (95% CI: 1.8%, 13.4%) overall increase in 2012-2019 relative to the trend in preceding years with no attenuation during 2012-19. The increase translates to 590 (165, 1226) excess perinatal deaths (p = 0.016). It is characterized by annual peaks with maxima in April. A 13.6% increase is determined in the four core prefectures and a 4.3% increase in eight prefectures surrounding the core prefectures. Before 2012, there is a peak around April 2011 and a decline in October 2011; another significant peak is detected in November 2012. In the 4 core prefectures, large increases are found in the first quarter of 2018 (+70%) and in May 2019 (+130%).

CONCLUSION

This study finds periodic peaks in perinatal mortality in spring 2012-2019 in 12 prefectures of Japan surrounding the FDNPP. In light of massive increases in 2018 and 2019 in the four core prefectures, continued investigation of perinatal mortality in contaminated regions of Japan is recommended.

Increases in perinatal mortality in prefectures contaminated by the Fukushima nuclear power plant accident in Japan: A spatially stratified longitudinal study

Descriptive observational studies showed upward jumps in secular European perinatal mortality trends after Chernobyl. The question arises whether the Fukushima nuclear power plant accident entailed similar phenomena in Japan. For 47 prefectures representing 15.2 million births from 2001 to 2014, the Japanese government provides monthly statistics on 69,171 cases of perinatal death of the fetus or the newborn after 22 weeks of pregnancy to 7 days after birth. Employing change-point methodology for detecting alterations in longitudinal data, we analyzed time trends in perinatal mortality in the Japanese prefectures stratified by exposure to estimate and test potential increases in perinatal death proportions after Fukushima possibly associated with the earthquake, the tsunami, or the estimated radiation exposure. Areas with moderate to high levels of radiation were compared with less exposed and unaffected areas, as were highly contaminated areas hit versus untroubled by the earthquake and the tsunami. Ten months after the earthquake and tsunami and the subsequent nuclear accident, perinatal mortality in 6 severely contaminated prefectures jumped up from January 2012 onward: jump odds ratio 1.156; 95% confidence interval (1.061, 1.259), P-value 0.0009. There were slight increases in areas with moderate levels of contamination and no increases in the rest of Japan. In severely contaminated areas, the increases of perinatal mortality 10 months after Fukushima were essentially independent of the numbers of dead and missing due to the earthquake and the tsunami. Perinatal mortality in areas contaminated with radioactive substances started to increase 10 months after the nuclear accident relative to the prevailing and stable secular downward trend. These results are consistent with findings in Europe after Chernobyl. Since observational studies as the one presented here may suggest but cannot prove causality because of unknown and uncontrolled factors or confounders, intensified research in various scientific disciplines is urgently needed to better qualify and quantify the association of natural and artificial environmental radiation with detrimental genetic health effects at the population level.

The evidence of radiation effects in embryos and fetuses exposed to Chernobyl fallout and the question of dose response

Current legal frameworks for radiation exposure limits are based on the risk models of the International Commission on Radiological Protection (ICRP). In Publication 90 (2003), ICRP presents a safe (threshold) dose range of up to 100 mSv for radiogenic effects resulting from in utero exposure and bases this conclusion on the findings in Hiroshima and Nagasaki. However, a variety of observations of congenital malformations, fetal loss, stillbirths and infant deaths, as well as of Down's syndrome and other health defects in children after the Chernobyl accident exposures suggest that the A-bomb survivor data are incomplete. The Chernobyl findings are generally marginalized or even denied because of the low values of the estimated human exposures and the inconsistency of the results with the accepted risk models. One explanation for the observations is that physical dosimetric models have underestimated the effective exposure. This possibility is supported by biological dosimetry in the contaminated regions. The assumptions about effects after in utero exposure by incorporated radionuclides need to be revised.